Yea I know....this has been touched on a million times and I read about half of the posts but nothing that really identified a common culprit other than the carb upgrade.

Here is my problem-

Just got a 2002 Sportsman 700 with 500 miles and it is beautiful....BUT....after I got it home last night and idled it for about 5 minutes it started to sputter and run crappy. After that, it wouldn't stay running at idle w/o giving it a little gas manually (and it was still choppy) but if you juice the throttle it seems pretty crisp and takes the gas well. After poking around for a few minutes I came across two noticable problems-
1. It is spewing fuel into the airbox from the vent line that comes from the head area.
2. It totally blackens plugs after running for a few minutes. I cleaned em up and put em back in and it ran noticably better for a few minutes and back to the sputtering and black plugs.

So....clearly running way too rich. Is there a typical hangup in the carb that causes this type of thing? I mean like a specific part that gets gunked up, etc?


Also, side note, I know these things are famous for being a little noisy, but is the noise typical right near your right foot? Kind of a metal clacking sound?? It does not get worse with throttle so that makes me feel a little better....